From 45e481ce445dbbfdb04c7797c204f81c6c44844e Mon Sep 17 00:00:00 2001
From: Tom Thorogood <me+github@tomthorogood.co.uk>
Date: Thu, 27 Sep 2018 16:17:48 +0930
Subject: [PATCH] Fix unpackString bug: 127 DEL is unprintable (#755)

This case previously differed from UnpackDomainName in
msg.go and both sprintTxtOctet and appendTXTStringByte in
types.go and was incorrect.
---
 msg_helpers.go      | 2 +-
 msg_helpers_test.go | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/msg_helpers.go b/msg_helpers.go
index e8c6b745..d58ff1d7 100644
--- a/msg_helpers.go
+++ b/msg_helpers.go
@@ -275,7 +275,7 @@ func unpackString(msg []byte, off int) (string, int, error) {
 		case b == '"' || b == '\\':
 			s.WriteByte('\\')
 			s.WriteByte(b)
-		case b < 32 || b > 127: // unprintable
+		case b < ' ' || b > '~': // unprintable
 			var buf [3]byte
 			bufs := strconv.AppendInt(buf[:0], int64(b), 10)
 			s.WriteByte('\\')
diff --git a/msg_helpers_test.go b/msg_helpers_test.go
index df1fbfae..ebeac84d 100644
--- a/msg_helpers_test.go
+++ b/msg_helpers_test.go
@@ -108,7 +108,7 @@ func TestPackDataNsec(t *testing.T) {
 }
 
 func TestUnpackString(t *testing.T) {
-	msg := []byte("\x00abcdef\x0f\\\"ghi\x04mmm")
+	msg := []byte("\x00abcdef\x0f\\\"ghi\x04mmm\x7f")
 	msg[0] = byte(len(msg) - 1)
 
 	got, _, err := unpackString(msg, 0)
@@ -116,7 +116,7 @@ func TestUnpackString(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	if want := `abcdef\015\\\"ghi\004mmm`; want != got {
+	if want := `abcdef\015\\\"ghi\004mmm\127`; want != got {
 		t.Errorf("expected %q, got %q", want, got)
 	}
 }